Hyperopia or farsightedness results from a combined cornea/crystalline lens that provide too little refractive power in relation to the axial length of the eye. Light rays focus behind the retina rather than immediately in front of it. Individuals with a mild degree of hyperopia can usually compensate for the visual dysfunction by accommodating or using the crystalline lens' focusing capacity, sometimes resulting in headaches and eye strain. Glass or lenses with a positive correcting power are used for hyperopes.
The image enlargement that occurs when viewing objects through spectacles can be problematic for hyperopes who require correction of +4D or beyond. This may be related to optic disc size in these individuals and the disc's proximity to the fovea, where sharpest vision is obtained.4 Contact lenses with a toric back surface are often a more visually comfortable alternative for a severely hyperopic person.
Farsighted individuals who approach the age of presbyopia, at approximately 40 years of age, generally require stronger positive lenses for viewing objects up close.
4 Optic Disk Size correlated with Refractive Error, Dept of Ophthalmology, Faculty of Clinical Medicine Mannheim, U. of Heidelberg, Mannheim ,GE